Pultrusion Line Speed Optimization

This weekend we started our new contract with a pultrusion company to improve their products quality and also lowering their process costs. So we started with the weakest point in the factory which was related to their slow and improper curing system.

I prepared an action plan with my assistant (Miss Kosar) to evaluate their available peroxides. We did semi SPI gel time tests for 5 single peroxides and 3 mixed of them. I named the tests semi SPI because we did them at 125 oC (process temperature) instead of standard mentioned temperature 82 oC. The results were shown in below:

As can be seen in the figure above the peroxides started curing in different temperature and produced different amount of exothermic heat of reaction. So based on his graph, we strongly rejected Dual 4&3 because of fast curing reaction with high exotherm and decided to evaluate two dual systems of 5&4 and 4&1 because of their more activation and lower exotherm.

So we lunch the pultrusion process by these formulation and the results were great. We could increase the line speed from current speed of 10 cm/min to 55 cm/min for Dual 5&4 and 35 cm/min for Dual 4&1. The apparent quality of the products was excellent too.

After completing gel time tests and doing pultruding the formulation, it was line speed optimization turn! We put a thermometer in the impregnated fibers and let it pass the die and we recorded the temperature. We had to did this action several times to confirm that the curing reaction is completed at the end of die length.

You can see on graph in below for 4&1 Dual system:

From that graph, it can be realized that the curing reactions were completed 20 cm before the end of die and the line speed can be increased.

At the end of job, everyone feel happy specially the owner because he could produce 5 times more with the same equipment, workers and time! My assistant will continue the action plan for a month to determine the best line speed for each product.